Bump on axolotl tail

My 10 month old gold albino axolotl, and his wildtype brother have both developed some little bumps on their tails. Only on the tails.The gold albino has two, the largest can be seen in the picture attached. I am not sure why they are getting these bumps. They start off almost as little cones only on their tails and then grow a little bigger and stop. The one in the picture is the size of a small pea. Both axolotls are still growing and extremely healthy otherwise. Doesn't seem to affect them at all. I just wanted to see if anyone knew what the deal was and if there is something i'm doing wrong? I thought it might be a tumor at first but since they both get them I doubt thats it. Maybe a parasite? I love them so much and want to do everything I can for them. Any ideas what this is? I've heard they can just develope skin tags? Any help would be so appreciated. Thanks guys.

They look like small cysts or abscesses. If they don't change in shape/color, they're probably of little concern. If they start getting bigger, or redder, you should consult a vet for removal.

Thank you for the response! Yea they start of small....reach a certain size and then stop growing. So its not like they are getting really big. Thanks again I'm gonna keep an eye on it.